A162257 a(n) = (2*n^3 + 5*n^2 - 11*n)/2.

-2, 7, 33, 82, 160, 273, 427, 628, 882, 1195, 1573, 2022, 2548, 3157, 3855, 4648, 5542, 6543, 7657, 8890, 10248, 11737, 13363, 15132, 17050, 19123, 21357, 23758, 26332, 29085, 32023, 35152, 38478, 42007, 45745, 49698, 53872, 58273, 62907, 67780

Offset: 1

Author

Vincenzo Librandi, Jun 29 2009

Keywords

• sign
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1).

Crossrefs

Cf. A155550.

Programs

Maple

A162257:=n->(2*n^3+5*n^2-11*n)/2: seq(A162257(n), n=1..80); # Wesley Ivan Hurt, Jan 30 2017

Mathematica

CoefficientList[Series[(-2+15*x-7*x^2)/(1-x)^4,{x,0,40}],x] (* or *) LinearRecurrence[{4, -6, 4, -1}, {-2, 7, 33, 82}, 50] (* Vincenzo Librandi, Mar 04 2012 *)

Formula

Row sums from A155550: a(n) = Sum_{m=1..n} 2*m*n + m + n - 6.

From Vincenzo Librandi, Mar 04 2012: (Start)

G.f.: x*(-2 + 15*x - 7*x^2)/(1-x)^4.

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)

Extensions

New name from Vincenzo Librandi, Mar 04 2012